scholarly journals It Cuts Both Ways: An Annelid Model System for the Study of Regeneration in the Laboratory and in the Classroom

2021 ◽  
Vol 9 ◽  
Author(s):  
Veronica G. Martinez Acosta ◽  
Fausto Arellano-Carbajal ◽  
Kathy Gillen ◽  
Kay A. Tweeten ◽  
Eduardo E. Zattara
Keyword(s):  
Wound Healing ◽  
Developmental Process ◽  
Recovery Of Function ◽  
Single Species ◽  
Model System ◽  
Regenerative Capacity ◽  
Closely Related Species ◽  
Complete Replacement ◽  
Successful Recovery ◽  
The Individual

The mechanisms supporting regeneration and successful recovery of function have fascinated scientists and the general public for quite some time, with the earliest description of regeneration occurring in the 8th century BC through the Greek mythological story of Prometheus. While most animals demonstrate the capacity for wound-healing, the ability to initiate a developmental process that leads to a partial or complete replacement of a lost structure varies widely among animal taxa. Variation also occurs within single species based on the nature and location of the wound and the developmental stage or age of the individual. Comparative studies of cellular and molecular changes that occur both during, and following, wound healing may point to conserved genomic pathways among animals of different regenerative capacity. Such insights could revolutionize studies within the field of regenerative medicine. In this review, we focus on several closely related species of Lumbriculus (Clitellata: Lumbriculidae), as we present a case for revisiting the use of an annelid model system for the study of regeneration. We hope that this review will provide a primer to Lumbriculus biology not only for regeneration researchers but also for STEM teachers and their students.

scholarly journals THE SPECIFICITY OF OXIDIZED AND REDUCED PROTEINS OF THE OCULAR LENS

1940 ◽  
Vol 71 (5) ◽  
pp. 585-590 ◽  
Author(s):  
E. E. Ecker ◽  
L. Pillemer
Keyword(s):  
Related Species ◽  
Redox State ◽  
Single Species ◽  
Species Specificity ◽  
Ocular Lens ◽  
Closely Related Species ◽  
Pure Compounds

Oxidized and reduced proteins were prepared from the ocular lenses of sheep, swine, chicken and fish (pike). The proteins were prepared under conditions designed to avoid denaturation and to produce relatively pure compounds. Serologic studies revealed that species specificity is demonstrable in the proteins from chicken and fish lenses, but in the more closely related species (swine and sheep) this characteristic is not so evident. Serologic differences may be detected in the lens preparations from a single species, depending on the redox state of the protein.

scholarly journals Vocationalization of education in Kenya: the Classroom Practice and the Learners’ Responsibilities for Change in the 21st Century

2011 ◽  
Vol 1 (1) ◽  
pp. 142
Author(s):  
Samson Ondigi ◽  
Henry Ayot ◽  
Kiio Mueni ◽  
Mary Nasibi
Keyword(s):  
Political Development ◽  
Classroom Practice ◽  
History Of Education ◽  
Status Quo ◽  
Knowledge And Skills ◽  
Successful Recovery ◽  
Common Practices ◽  
The Status ◽  
History Of ◽  
The Individual

Abstract The essence of education is to prepare an individual for lifelong experiences after schooling. Education as offered in schools today is expected to give the teacher a chance to impart knowledge and skills in the learner, and for the learner to be informed and be able to put into practice what has been gained in the course of time. The Kenyan curriculum and goals of education are clearly stipulated if followed to the latter. Basically, the classroom practice by both the teachers and the learners exhibit an academic rather than a dual system that is expected to meet the needs of both the individual and those of the communities which form subsets of the society at large. It is upon this premise that education of a given country must prepare its individuals in schools so as to meet the goals of education at any one given time of a country’s history. This paper looks at the perspective of vocationalization of education in Kenyan at this century. The history of education ever since independence in 1963 by focusing on the Ominde commission through the Koech report of 1999 have been emphatic that education must meet the national goals of education as stipulated in the curriculum. But what is edging the practice that has not revolutionalized the socio-economic, cultural and political development of Kenya? Differentiated Instruction is a teaching theory based on the premise that instructional approaches should vary and be adapted in relation to individual and diverse students in classroom aimed at achieving diversified learning and common practices in the career. The challenges herein are: where have we gone wrong as a nation, what is the practice in the classroom, when can the nation be out of this dilemma, who is to blame for the status quo and finally what is the way forward? By addressing these questions, the education system will be responsive to the changes in time and Kenya will be on the path to successful recovery.

scholarly journals Extracting Interface Correlations from the Pair Distribution Function of Composite Materials

2021 ◽  
Author(s):  
Harry Geddes ◽  
Henry D. Hutchinson ◽  
Alex R Ha ◽  
Nicholas P. Funnell ◽  
Andrew Goodwin
Keyword(s):  
Distribution Function ◽  
Pair Distribution Function ◽  
Functional Materials ◽  
Model System ◽  
Complex Mixtures ◽  
Proof Of Concept ◽  
X Ray ◽  
The Individual ◽  
Theory And Experiment ◽  
Matrix Factorisation

<div> <div> <div> <p>Using a non-negative matrix factorisation (NMF) approach, we show how the pair distribution function (PDF) of complex mixtures can be deconvolved into the contributions from the individual phase components and also the interface between phases. Our focus is on the model system Fe||Fe3O4. We establish proof-of-concept using idealised PDF data generated from established theory-driven models of the Fe||Fe3O4 interface. Using X-ray PDF measurements for corroded Fe samples, and employing our newly-developed NMF analysis, we extract the experimental interface PDF (‘iPDF’) for this same system. We find excellent agreement between theory and experiment. The implications of our results in the broader context of interface characterisation for complex functional materials are discussed. </p> </div> </div> </div>

scholarly journals The coprome: another model system – abstract

1988 ◽  
Vol 94 ◽  
pp. 47-47
Author(s):  
R. C. Cooke ◽  
H. O. Safar ◽  
S. N. Wood
Keyword(s):  
Single Species ◽  
Model System ◽  
Sordaria Macrospora ◽  
Available Nutrients ◽  
Degradation Rates ◽  
Species Mixtures

The ability of Ascobolus crenulatus Karsten, Chaetomium bostrychodes Zopf and Sordaria macrospora Auersw. to produce biomass within, fruit upon, and degrade rabbit faeces was followed using semi-natural faecal resource units (copromes) (Wood & Cooke 1984, 1987). On these criteria the performance of the fungi was in the order C. bostrychodes > S. macrospora > A. crenulatus. Species mixtures produced only slightly higher degradation rates than those effected by single species. This implied competition for available nutrients which was also indicated by depressed fruiting of all species in species mixtures when compared with fruiting levels of each species grown individually. For single species the time of onset and subsequent fruiting level were determined by the time at which sufficient resources could be allocated to reproduction rather than simply to hyphal extension rates.

scholarly journals Expression of the neuropeptide SALMFamide-1 during regeneration of the seastar radial nerve cord following arm autotomy

2019 ◽  
Vol 286 (1901) ◽  
pp. 20182701 ◽  
Author(s):  
Maria Byrne ◽  
Franca Mazzone ◽  
Maurice R. Elphick ◽  
Michael C. Thorndyke ◽  
Paula Cisternas
Keyword(s):  
Wound Healing ◽  
Nervous System ◽  
Nerve Cord ◽  
Radial Nerve ◽  
Model System ◽  
Rapid Recovery ◽  
Nerve Stump ◽  
Rapid Access ◽  
Migratory Cells ◽  
Rapid Appearance

Arm loss through a separation at a specialized autotomy plane in echinoderms is inextricably linked to regeneration, but the link between these phenomena is poorly explored. We investigated nervous system regeneration post-autotomy in the asteriid seastar Coscinasterias muricata , focusing on the reorganization of the radial nerve cord (RNC) into the ectoneural neuroepithelium and neuropile, and the hyponeural region, using antibodies to the seastar-specific neuropeptide SALMFamide-1 (S1). Parallel changes in the associated haemal and coelomic vessels were also examined. A new arm bud appeared in 3–5 days with regeneration over three weeks. At the nerve stump and in the RNC immediately behind, the haemal sinus/hyponeural coelomic compartments enlarged into a hypertrophied space filled with migratory cells that appear to be involved in wound healing and regeneration. The haemal and coelomic compartments provided a conduit for these cells to gain rapid access to the regeneration site. An increase in the number of glia-like cells indicates the importance of these cells in regeneration. Proximal to the autotomy plane, the original RNC exhibited Wallerian-type degeneration, as seen in disorganized axons and enlarged S1-positive varicosities. The imperative to regrow lost arms quickly is reflected in the efficiency of regeneration from the autotomy plane facilitated by the rapid appearance of progenitor-like migratory cells. In parallel to its specialization for defensive arm detachment, the autotomy plane appears to be adapted to promote regeneration. This highlights the importance of examining autotomy-induced regeneration in seastars as a model system to study nervous system regeneration in deuterostomes and the mechanisms involved with the massive migration of stem-like cells to facilitate rapid recovery.

Developing Athletes in the Context of Sport and Performance Psychology

2017 ◽  
Author(s):  
Luc J. Martin ◽  
David J. Hancock ◽  
Jean Côté
Keyword(s):  
Social Environment ◽  
Physical Environment ◽  
Developmental Process ◽  
Sport Performance ◽  
Performance Psychology ◽  
The Social ◽  
Early Specialization ◽  
And Performance ◽  
The Individual ◽  
Athletic Development

Talent development in sport is achieved through years of preparation and requires constant interaction between personal and contextual resources. Accordingly, extensive research has been dedicated to understanding factors that contribute to sport performance. Literature suggests the factors influencing athletic development can be classified in terms of the physical environment, the social environment, and engaging learning activities. Investigations pertaining to the physical environment suggest the importance of appropriate settings, which can relate to the sport organization or the larger community. Researchers must also cogitate the activities in which athletes take part. These considerations involve the maturational status of athletes, the volume of deliberate practice and play, and early specialization versus diversification. Finally, the salience of the social environment in relation to sport performance cannot be overlooked. Not surprisingly, the relations established with social agents (i.e., coaches, peers/teammates, parents) can facilitate or impede the developmental process. Consequently, the development of athletes in the context of sport and performance psychology extends past the individual and is influenced by several factors that must be discussed.

scholarly journals Mutant CFTR Drives TWIST1 mediated epithelial–mesenchymal transition

2020 ◽  
Vol 11 (10) ◽  
Author(s):  
Margarida C. Quaresma ◽  
Ines Pankonien ◽  
Luka A. Clarke ◽  
Luís S. Sousa ◽  
Iris A. L. Silva ◽  
...  
Keyword(s):  
Cystic Fibrosis ◽  
Wound Healing ◽  
Transcription Factors ◽  
Developmental Process ◽  
Epithelial Mesenchymal Transition ◽  
Tumour Suppressor ◽  
Cell Junctions ◽  
Impaired Wound Healing ◽  
Mesenchymal Transition ◽  
Wide Range

Abstract Cystic fibrosis (CF) is a monogenetic disease resulting from mutations in the Cystic Fibrosis Transmembrane conductance Regulator (CFTR) gene encoding an anion channel. Recent evidence indicates that CFTR plays a role in other cellular processes, namely in development, cellular differentiation and wound healing. Accordingly, CFTR has been proposed to function as a tumour suppressor in a wide range of cancers. Along these lines, CF was recently suggested to be associated with epithelial–mesenchymal transition (EMT), a latent developmental process, which can be re-activated in fibrosis and cancer. However, it is unknown whether EMT is indeed active in CF and if EMT is triggered by dysfunctional CFTR itself or a consequence of secondary complications of CF. In this study, we investigated the occurrence of EMT in airways native tissue, primary cells and cell lines expressing mutant CFTR through the expression of epithelial and mesenchymal markers as well as EMT-associated transcription factors. Transepithelial electrical resistance, proliferation and regeneration rates, and cell resistance to TGF-β1induced EMT were also measured. CF tissues/cells expressing mutant CFTR displayed several signs of active EMT, namely: destructured epithelial proteins, defective cell junctions, increased levels of mesenchymal markers and EMT-associated transcription factors, hyper-proliferation and impaired wound healing. Importantly, we found evidence that the mutant CFTR triggered EMT was mediated by EMT-associated transcription factor TWIST1. Further, our data show that CF cells are over-sensitive to EMT but the CF EMT phenotype can be reversed by CFTR modulator drugs. Altogether, these results identify for the first time that EMT is intrinsically triggered by the absence of functional CFTR through a TWIST1 dependent mechanism and indicate that CFTR plays a direct role in EMT protection. This mechanistic link is a plausible explanation for the high incidence of fibrosis and cancer in CF, as well as for the role of CFTR as tumour suppressor protein.

scholarly journals β-Catenin drives distinct transcriptional networks in proliferative and nonproliferative cardiomyocytes

Development ◽  
2020 ◽  
Vol 147 (22) ◽  
pp. dev193417
Author(s):  
Gregory A. Quaife-Ryan ◽  
Richard J. Mills ◽  
George Lavers ◽  
Holly K. Voges ◽  
Celine J. Vivien ◽  
...  
Keyword(s):  
Developmental Process ◽  
Transcriptional Profiling ◽  
Neonatal Mouse ◽  
Transcriptional Networks ◽  
Cardiomyocyte Proliferation ◽  
Regenerative Capacity ◽  
Adult Heart ◽  
Glycolytic Gene

ABSTRACTThe inability of the adult mammalian heart to regenerate represents a fundamental barrier in heart failure management. By contrast, the neonatal heart retains a transient regenerative capacity, but the underlying mechanisms for the developmental loss of cardiac regenerative capacity in mammals are not fully understood. Wnt/β-catenin signalling has been proposed as a key cardioregenerative pathway driving cardiomyocyte proliferation. Here, we show that Wnt/β-catenin signalling potentiates neonatal mouse cardiomyocyte proliferation in vivo and immature human pluripotent stem cell-derived cardiomyocyte (hPSC-CM) proliferation in vitro. By contrast, Wnt/β-catenin signalling in adult mice is cardioprotective but fails to induce cardiomyocyte proliferation. Transcriptional profiling and chromatin immunoprecipitation sequencing of neonatal mouse and hPSC-CMs revealed a core Wnt/β-catenin-dependent transcriptional network governing cardiomyocyte proliferation. By contrast, β-catenin failed to re-engage this neonatal proliferative gene network in the adult heart despite partial transcriptional re-activation of a neonatal glycolytic gene programme. These findings suggest that β-catenin might be repurposed from regenerative to protective functions in the adult heart in a developmental process dependent on the metabolic status of cardiomyocytes.

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